16NOTE:• In the ntp-service unicast-server command, ip-address must be a unicast address. It cannot be abroadcast address, a multicast address or the IP address of the local clock.• When the source interface for NTP messages is specified by the source-interface keyword, the sourceIP address of the NTP messages is configured as the primary IP address of the specified interface.• A device can act as a server to synchronize the clock of other devices only after its clock has beensynchronized. If the clock of a server has a stratum level higher than or equal to that of a client’sclock, the client will not synchronize its clock to that server’s clock.• You can configure multiple servers by repeating the ntp-service unicast-server command. The clientswill select the optimal reference source.Configuring the NTP symmetric peers modeFor devices working in symmetric mode, specify a symmetric-passive peer for a symmetric-active peer.Following these steps to specify a symmetric-passive peer on the active peer:To do… Use the command… RemarksEnter system view system-view —Specify asymmetric-passive peer forthe devicentp-service unicast-peer { ip-address |peer-name } [ authentication-keyid keyid |priority | source-interface interface-typeinterface-number | version number ] *RequiredNo symmetric-passive peer isspecified by default.NOTE:• In symmetric mode, use the any NTP configuration command in Configuring the operation modes ofNTP to enable NTP. Otherwise, a symmetric-passive peer will not process NTP messages from asymmetric-active peer.• In the ntp-service unicast-peer command,ip-address must be a unicast address, rather than abroadcast address, a multicast address or the IP address of the local clock.• When the source interface for NTP messages is specified by the source-interface keyword, the source IPaddress of the NTP messages is configured as the primary IP address of the specified interface.• Typically, at least one of the symmetric-active and symmetric-passive peers has been synchronized.Otherwise the clock synchronization will not proceed.• You can configure multiple symmetric-passive peers by repeating the ntp-service unicast-peercommand.Configuring NTP broadcast modeThe broadcast server periodically sends NTP broadcast messages to the broadcast address255.255.255.255. After receiving the messages, the device working in NTP broadcast client modesends a reply and synchronizes its local clock.For devices working in broadcast mode, configure both the server and the clients. NTP broadcast modecan be configured only in the specific interface view, because an interface needs to be specified on thebroadcast server for sending NTP broadcast messages and an interface also needs to be specified oneach broadcast client for receiving broadcast messages.
